As is well known, trees and plants through the process of photosynthesis naturally convert CO2 into oxygen. When nature cannot do its job, chemistry takes over. In maimed, enclosed atmospheres such as rescue chambers, dive devices or submarines, two chemical technologies have historically been employed to scrub the CO2 from the environment: lithium hydroxide and soda lime. Below are the pros and cons of both materials.
Soda Lime w/ ScrubberLithium Hydroxide CurtainsCO2 Absorption:150 liters CO2 per kg402 liters CO2 per kgPackaging:20 kg (44 lb) sealed kegs8 curtains per box; 5.72 lbs ofLiOH per box.96 Hr Requirements:1 keg per man2.75 boxes per manPer MSHA: (.244 lbs/man − hr) * 96 hr/5.72 lbs/box = 4.1 boxesApprox Cost/unit:$135/keg$487/boxCost/man for 96 hrs:$135/man$1339/man$1997/man per MSHAShelf Life:5 years5 yers; must be discardedHeat Generated:32 Btu's per man per hour130 Btu's per man per hour;curtains actually hot to the touchDeployment:Simple; new keg addedComplicated; curtains must bewhen color changeshung at a set schedule and spacingEffectiveness:good air circulation fromonly works in small, confined areas;Air driven fannot effective in large areasPower Requirements:None; air/oxygen driven fanNone; passive system relies onlocalized natural convective currents